Pulse-amplitude equalization in a rational harmonic mode-locked semiconductor fiber ring laser using a dual-drive Mach-Zehnder modulator

Abstract

We present and demonstrate a simple method of pulse-amplitude equalization in a rational harmonic mode-locked semiconductor ring laser, using a dual-drive Mach-Zehnder (MZ) modulator. Pulse-amplitude equalization was achieved by adjusting the voltages applied to both arms of the modulator, such that each mode-locked pulse experiences the same transmission coefficient in the transmission curve of the modulator. With this method, amplitude-equalized pulse trains with repetition rates of ~7.41GHz (third rational harmonic) and ~12.34GHz (fifth rational harmonic) were successfully obtained without any additional function to the ring laser itself.